Obtaining & Using Metals (Edexcel GCSE Chemistry: Combined Science)

A student carried out an experiment to see how reactive different metals are when they are placed in dilute hydrochloric acid.
A sample of each metal was placed in a separate test tube of acid.

When zinc reacts with dilute hydrochloric acid, a gas is given off and zinc chloride is formed.

In the experiment, the student used the same amount of each metal in a finely powdered form.

State two factors, concerning the hydrochloric acid, which should also be controlled to produce valid results.

Part of the reactivity series is shown in Figure 8.

Figure 8

Iron is extracted from its ore by heating with carbon.
Aluminium is extracted from its ore using a different method.

(1)

(2)

The extraction of iron involves the reduction of iron oxide, Fe₂O₃, by carbon monoxide, CO. During this reaction, the iron oxide is reduced to iron, Fe, and the carbon monoxide is oxidised to carbon dioxide.

Write the balanced equation for the reaction.

Some metals, such as aluminium, are extracted from their ores using electrolysis. 

Why are some metals extracted using electrolysis? 

Most metals are extracted from ores found in the Earth’s crust.

The method used to extract a metal from its ore is linked to the reactivity of the metal.

Part of the reactivity series is shown in Figure 14.

Figure 14

Iron ore contains iron oxide.

Iron is extracted from iron oxide by heating the oxide with carbon.

Aluminium cannot be extracted by heating its oxide with carbon.

Aluminium has to be extracted from its oxide by electrolysis.

Explain why.

Predict the method that will have to be used to extract calcium from its ore.

Aluminium is extracted from its ore by electrolysis.

Iron is extracted from its ore by heating with carbon.

Both metals can also be obtained by recycling.

Explain the advantages of recycling aluminium and iron rather than extracting them from their ores.

Higher Only

In recent years, researchers have been investigating alternative methods of extracting metals from soils.

Researchers have found that growing certain plants in appropriate areas can result in the phytoextraction of copper.

Describe how growing plants can result in the phytoextraction of copper.

Which of the following metals can not be extracted from its ore by reduction?

Metals are extracted from substances naturally occurring in the Earth’s crust.

Which of these metals is usually found uncombined in the Earth's crust? 

Zinc can be extracted by heating zinc oxide with carbon.

The products are zinc and carbon dioxide.

Aluminium is extracted from aluminium oxide by electrolysis.

Aluminium oxide is made up of ions.

A student was investigating the reactivity of different metals in hydrochloric acid. 

What must the student keep constant in this investigation to make it a fair experiment?

(1)

Higher Only

One way to extract metals from land contaminated with metal compounds is phytoextraction.

When plants grow they absorb metal ions through their roots.

The plants are harvested, dried and burned forming an ash.

The ash contains metal compounds.

Plants were grown in a piece of ground contaminated with nickel compounds.

Some nickel ores contain nickel sulfide.

(2)

(1)

The boiling point of nickel tetracarbonyl is 43 °C.
The boiling point of iron pentacarbonyl is 103 °C.
These two liquids mix together completely. 

Describe the process used to separate these two liquids.

Some metals are unreactive and exist on their own in the earth. 

What are these metals known as?

Pieces of zinc react with copper sulfate solution.
Zinc sulfate solution is colourless.

Zn (s) + CuSO₄ (aq) → Cu (s) + ZnSO₄ (aq)

Higher Only

This reaction is described as a redox reaction.

Explain, in terms of electrons, which particles have been oxidised and which particles have been reduced in this reaction.

Higher Only

The copper sulfate solution used has a concentration of 15.95 g dm⁻³.

Calculate the number of moles of copper sulfate, CuSO₄, in 50.00 cm³ of this solution.

In another experiment, 0.043 mol of copper sulfate, CuSO₄, is used.

Calculate, to one decimal place, the minimum mass of zinc that must be added to react with all the copper sulfate.

Zinc is extracted from zinc oxide by reduction.

Which element is oxidised during this process?

Some metals are found in the Earth’s crust as uncombined elements.
Reactive metals are found in ores.

In ores, metals are combined with other elements.

Which of these metals is found as the uncombined element in the Earth’s crust?

Give two advantages of recycling metals rather than extracting metals from their ores.

An ore of iron is mostly iron oxide, Fe₂O₃.
Iron can be extracted from this iron oxide by heating it with carbon.

Balance this equation for the reaction that takes place.

Most copper ores are described as low grade.
This means that the percentage of copper in the ore is very small.

5000 kg of one copper ore was found to contain 42.5 kg of copper.

Calculate the percentage of copper in this ore.

In one stage of the extraction of lead from its ore, lead oxide is heated strongly with carbon.

The equation for the reaction is 

Explain, using this equation, which substance has been oxidised in this reaction.

A titanium ore was analysed and found to contain 12 g of titanium atoms combined with 8.0 g of oxygen atoms.

Calculate the empirical formula of this titanium compound.
(relative atomic masses: Ti = 48, O = 16)

You must show your working.

Coffee cups are usually made from ceramic, glass, paper, plastic or metal.

Some of these materials are recyclable. In a Life Cycle Assessment (LCA) where would this information be given?

When chromium reacts with oxygen, chromium oxide is formed.

(1)

............... + ................ → ..............

(1)

(2)

relative formula mass = .............................................................

Three different metals are added to separate test tubes of acid.

The observations are shown in Figure 4.

Figure 4

(1)
most reactive .............................................................

least reactive .............................................................

(1)

(1)

Iron is extracted by heating iron oxide with carbon.

Electrolysis of molten iron oxide is not used to extract iron.

(1)

Higher Only 

Copper can be extracted from low grade ores using bioleaching. 

A leachate solution is produced.

Which process is used to extract the copper from the leachate solution?

A reaction took place between iron sulfate and magnesium. 

iron(II) sulfate + magnesium  →    magnesium sulfate + iron 

Which species has been oxidised?

The order of reactivity of copper, magnesium and zinc can be determined by the displacement reactions between these metals and solutions of their salts.

You are provided with

• samples of the three metals
• solutions of copper sulfate, magnesium sulfate and zinc sulfate.

Describe the experiments that can be done to determine the order of reactivity of these metals by displacement reactions.

Metals can be extracted from ores found in the Earth’s crust.

Explain why aluminium cannot be extracted from its ore by heating with carbon but can be extracted by electrolysis.

Titanium is extracted from its ore in several stages.

In the first stage, titanium chloride is formed as a gas.

The gas is cooled to form liquid titanium chloride containing dissolved impurities.

Suggest how pure titanium chloride could be separated from the impurities.

Higher Only

In another stage, the pure titanium chloride, TiCl₄ , is reacted with 500 moles of magnesium, an excess.

TiCl₄ + 2Mg → Ti + 2MgCl₂

(2)
number of moles titanium chloride = ...............................................................

(1)

After this reaction, there is a mixture of the solids magnesium, titanium and magnesium chloride.

Titanium does not react with dilute hydrochloric acid.

Suggest a simple method to separate titanium from the mixture.

Phytomining can be used to extract copper compounds from the soil.

Plants are grown on the soil and they absorb the copper compounds through their roots.
The plants are then harvested, dried and burnt to form an ash.
The ash contains the copper compounds.

One example of a copper compound extracted this way is copper oxide.
The copper oxide is added to acid where it reacts to form copper sulfate solution.
Give the formula of the acid used in this reaction.

Higher Only

Copper is extracted from copper sulfate solution using scrap iron.

Explain why it is economical to use scrap iron for this function.

Explain why scrap iron can be used to extract copper from copper sulfate.

Higher Only

Describe one advantage of extracting copper by phytoextraction rather than from its ore.

Lead is found in the Earth’s crust in ores.
In ores, the lead is combined with other elements.

5000 kg of lead ore was found to contain 48 200 g of lead.

Calculate the percentage of lead in the ore.
Give your answer to 2 significant figures.

The lead ore contains lead oxide (PbO).
To extract lead from lead oxide it is heated strongly with carbon.

Write the balanced symbol equation for this reaction.

Explain which substance is oxidised, and which is reduced.

Figure 1 shows the reactivity series of metals.

A non-metal - carbon - has also been included.

Figure 1

Use Figure 1 to explain why:

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Calcium is added to a beaker of silver nitrate solution.

A reaction takes place.

The symbol equation for the reaction is:

Ca(s) + 2AgNO₃(aq) → Ca(NO₃)₂ (aq) + 2Ag(s)

Explain why this reaction happens in terms of reactivity.

Higher Only

Write the ionic equation for this reaction.

Higher Only

Explain why this reaction is an example of a redox reaction.

Potassium is more reactive than calcium.

Use the electronic structure of these elements to suggest why.

Figure 1 shows how five different metals - A, B, C and D react when heated in oxygen.

The same size and shape piece of metal was used for each.

Figure 1

Most of the metals undergo a chemical reaction.

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[1]

Order the metals in terms of reactivity, starting with the least reactive.

The same metals are added to dilute hydrochloric acid.

Write the balanced symbol equation when magnesium reacts with hydrochloric acid.

Predict what would be observed when:

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